Variable-speed driving mechanism



Feb. 7, 1928.

. A. W. BARTON ET Al.

VARIABLE SPEED DRIVING MECHANISM 2 Sheets-Sheet 1 Filed Jan. 15. 1926 NWBarton.

E4 DuLac M. Ferguson.

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Feb. 7, 1928. 1,658,279

A. W. BARTON ET AL VARIABLE SPEED DRIVING MECHANISM Patented Feb. 7,1928.

UNITED STATES PATENT OFFICE.

ALBERT W. BARTON, EDMUND DU LAC, AND EDWIN M. FERGUSON, OF MINNEAIOLIB,

MINNESOTA, ABBIGNORS TO HORTON MFG. COMPANY, OF MINNEAPOLIS, MINNI- som.

VARIABLE-SPEED DRIVING MECHANISM.

Application men January it, me. Serial No. $1,401.

Our invention relates to variable speed drivingmechanism, and an objectin general is to provide mechanism by means of which machines of variouskinds may be driven from a ried as esired. Another object is to providea pulley of this character having-mechanism associated therewith whichacts as a governor so that in case the ulley should from any causebecome speede -,up excessively, the shaft driven from the pulley willnot also be speededup. This invention is an improvement on that,disclosed in Patent No. 1,171,554, issued Feb. 15, 1916, to Charles P.Strite. An object in particular is to provide mechanism of this naturewhich is more sensitive and reliable in operation thanthat disclosed insaid patent. The full objects and advantages of our invention willappear in connection with the detailed description thereof, and thenovel features of our inventive idea will be particularl pointed out inthe claims.

In' t e accompanyin drawings which illustrate a practical em odiment ofour invention,'-

, Fig. 1 is a vertical sectional view of the mechanism. Fig. 2 is a viewtaken on the line 2-2 of Fig. 1. Fig. 3 is a view on an enlarged scalein section on the line 3-3 of Fig. 1 and turned through 90. Fi 4 is aview in section on the line 44 of ig. 3. Fi 5 is a detail view.

is illustrated in the drawings, a machine 10 which is to be operated hasa shaft 12 which extends outwardl therefrom. A

sleeve 14 surrounds the s aft 12, the inner end portion of this sleevebeing surrounded by a hub 16 which extends out from a transmission diskor spider 18.- A collar 20 surrounds the inner end of the hub 16. Threeset screws 22 which pass through the collar 20, the hub 16 and thesleeve14 serve to secure them to each other and to the shaft 12.

4 A sleeve 24 is mounted for oscillatory movement around the hub 16while a ring 26 is secured to said sleeve. A second ring 28 is mountedfor oscillatory movement on the sleeve 24. The adjacent sidesof thesetwo I0 rings have cooperating cam surfaces 30 and 32 respectively, therepreferably being three of these cam surfaces around each of the rin s.Ball bearings 34 with their retainers an spacing rings are interposedbetween the A ll collar 20 and the ring 26, while ball bearings ulley atspeeds which may be va- 36 with their retainers and spacing rings areinterposed between the ring 28 and a ring. 38. This latter ring has twopins 40 extending from the outer face thereof. These pins are located.at diametrically opposite points and one of them is shown in Fig. 5 andone of them is shown in dotted lines in Fig. 1.- These pins projectthrough openings in the disk 18 for a purpose which will presentlyappear. As best shown in Fig. 2, the rin 26 is provided with anoutwardly directe car 42 and the ring 28 is provided with an outwardlydirected car 44. A curved arm 46 is pivoted at one end to the ear 42 andits other end is turned outwardly to form a socket member 48. A secondcurved arm is pivoted at one end to the ear 44 and at its other end ispivoted to the base of the socket member 48. When the socket member 48is pulled outwardly, the rings 26 and 28 will e partially rotated inrelatively opposite directions and the cam surfaces 30 and 32 willcooperate to cause separation of the rin 26 and 28 which results in anoutward shi ting movement of the ring 38. When the socket member 48 ispushed inwardly, the rings 26 and 28 will be partially rotated inrelatively opposite directions and in directions op osite to theirformer movements, thus permitting the rings to come together and alsopermitting inward shifting movement of the ring 38. Stop lugs 49 and 51carried by the rings 26 and 28 will engage each other and determine theextent of turning movement of the rings when the socket member is pulledoutwardly as will be understood from Fig. 2. The socket member may beoperated in any suitable manner. As shown in Fi 2, the socket member isconnected by a 1'0 53 with a hand lever 52 which can be turned on a 95pivot 54 carried by its lower end and by a floor bracket 56. Referringagain to the ring 38, it will be understood from Fig. 1 that the pins 40which are carried by this ring after passing through the disk 18 engagean equalizing ring 58 and that the disk 18 is adjacent the inner end ofthe hub 60 of a pulley rim 62 connected by spokes 64 with said hub whichis rotatably mounted on I the sleeve 14. At diametrically opposite l 1points on the ring 58 coiled springs 66 are interposed between this ringand the free I ends of two curved lever arms 68. As best shown in Fig.3, the two arms 68 are pivoted at diametrically opposite places carriedon the inner surface of the disk 18 and which also pass through pairs ofspaced lugs 74. The lever arms 68 between the lugs 74 thereon carryadjustable set bolts 7 6. the heads of which engage levers 78 pivotednear one of their ends on pivots 80 carried by the disk 18. The longarms of the levers 78 have weights 82 at their ends and are urgedoutwardly by springs 84 which conncct them with the disk 18. Centrallypivoted onthe short arms of the levers 78 are equalizing arms 86 uponthe ends of which pairs of shoes or friction blocks 88 are pivotallymounted. Under ordinary conditions, the springs 84 hold the shoes 88 outof operating engagement with the inner surface of the pulley rim 62 sothat the pulley runs free on the sleeve 14 and does not impart rotationto the shaft 12. If, however, the spanner consisting of the curved arms46 and is pulled outwardly. this will result in the cam surfaces 30 and32 riding upon each other and will cause the pins 40 to move forwardlyand rock the arms 78 thereby forcing the shoes 88 into engagement withthe pulley rim 62. The frictional engagement of these shoes will causethe disk 18 and the shaft 12 to which it is secured to rotate. It willbe understood that when the rings 26 and 28 are close together in theposition shown in Fig. 5,-no movement will be imparted from the pulleyto the shaft 12.

The operation and advantagesof our invention will be readily understoodin connection with the foregoing description. Upon pulling outwardly thespanner consisting of the arms 46 and 50, pressure will be graduallyapplied to the springs 66 to force the shoes 88 into engagement with thepulley rim 62, for imparting rotation therefrom to the shaft 12 so thatthe latter will be started slowly. It the spanner is pulled outwardly toits full extent as determined by the stop lugs, the speed of the shaft12 will under ordinary conditions be accelerated until is reaches thespeed of the pulley. By pulling the spanner only part way outward, anydesired speed of the shaft 12 less than that of the pulley may beobtained. Furthermore, the mechanism will act as a governor since if thebelt B which drives the pulley becomes speeded up more than the desiredamount, centrifugal force will cause the weights 82 to move outwardlyand partly disengage the shoes from the pulley rim, thereby preventingspeeding up of the shaft 12. It will be apparent from Figs. 1 and 2 thatthe variable speed mechanism is made operable without any means forattaching it to the frame of the machine which is to be operated andthat it can he applied to short stub shafts. It will also be apparentfrom Fig. 1 that end thrust is avoided. The use of a spanner forrotating two cam devices in opposite directions and the mounting of thecam devices and thrust ball bearin on the hub of the transmission diskresu ts in an extremely reliable operation of the mechanism. Theemployment of the sleeve 14 and the surrounding sleeve 24 with which oneof the cam devices is rigidly connected prevents cutting of the hub 16to which the transmission disk is connected. The employment ofrelatively long lever arms 68 results in increased leverage and makes itpossible to use weaker springs. thereby making the mechanism moresensitive and reducin fluctuations in transmission. The provision of theequalizer ring 58 backed up by springs 66 and the provision of the ring38 carrying the pins 40 eliminates the long pins 31 and 32 and the thickcasting 23 shown in patent No. 1,171,554 previously referred to. Themaking of the friction shoes in two parts or in pairs connected by theequalizing arms 86 provides for variations or inequalities in the innersurface of the pulley rim 62. This surface even if accurately machinedwill not remain accurate on account of expansion and contraction of thespokes (34 of the pulley. The ring 58 acts as an equalizer due to thefact that the pins 40 engage this ring midway between the places thereofengaged by the springs 66 as will be seen from Fig. 3.

We claim:

1. In combination with a shaft, a power operated pulley on said shaft, atransmission member on said shaft, an e ualizing ring looselysurrounding said shaft, levers pivoted near their ends to saidtransmission member, weights on the long arms of said levers, springsnormally urging said long arms outwardly, friction shoes carried by theshort arms of said levers and normally held out of operative engagementwith the rim of said pulley by said springs, means for 0porating saidequalizing ring and connections between the latter and said short armsfor forcing said shoes into engagement with said pulley rim.

2. In combination with a shaft, a power operated pulley on said shaft, atransmission member on said shaft, an equalizing rin loosely surroundingsaid shaft, a pair 0 lever arms pivoted to said transmission member.coiled springs interposed between said ring and the free ends of saidlever arms, levers pivoted near their ends to said transmission membcrand having their short arms operatively engaged by said lever arms,weights on the long arms of said levers, springs normally urging saidlong arms outwardly, equalizing members centrally pivoted on the ends ofsaid short arms, friction shoes pivoted on each of the ends of saidequalizing members and normally held out of operative engagement withthe rim of said pulley by said last mentioned springs,

' is adapted to rotate, two

a pair ofthrust bearings surrounding said shaft, means for sliding oneof said thrust hearings to separate it from the other, a ring movablewith said slidable bearing, and pins carried by said movable ringextending through said transmission member into engagement with saidequalizing ring for forcing said shoes into engagement with said pulleyrim.

3. In combination with a shaft, a poweroperate-d pulley on said shaft, atransmission member on said shaft, an equalizing ring looselysurrounding said shaft on one side of said transmission member, a air oflever arms pivoted to said transmission member, springs interposedbetween said ring and the free ends of said lever arms, friction shoescarried by said transmission member normally out of operative engagementwith said pulley, connections between said lever arms and said shoes forforcing the latter into engagement with said pulley, a slidable memberon the other side of said transmission member and within which saidshaft ins carried by said slidable member extending through saidtransmission member into engagement with said equalizing ring midwaybetween the places thereof engaged by said sprin and means for movingsaid slidablemem er toward said equalizing ring.

4. In combination with a shaft, a powerpulley, connections between saidlever arms and said shoes for forcing the latter into engagement withsaid pulley, a movable memher for sliding said equalizing ring andhaving engagement therewith midway between the places thereof engaged bysaid springs,

and means for moving said movable member for operating sald equalizingring.

In testimony whereof wehereunto afiix, 50

our signatures.

ALBERT W. BARTON. EDMUND DU LAC. EDWIN M. FERGUSON.

